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Comments 120601 to 120650:

120601. HumanityRules at 16:58 PM on 25 April 2010
        Has Arctic sea ice returned to normal?
        There is something a little bit extraordinay about this years Arctic ice. The following show ice concentration, i.e. the % of sea covered by ice. Almost all the Arctic Ocean is covered by 100% ice (dark purple). Shown here are 1st Jan, 1st Feb, 1st Mar and 1st Apr 2010. Compare this with the earliest winter on record, 1980. You can see much more pale purple regions, suggesting areas with as little as 80% coverage. 2007 didn't look great but then neither did 1986, most years seem to look like 1980. The images are generated using a tool on the Cryosphere Today website where you can check as much of the intervening years as you wish. 2010 looks so good you can't help thinking it's a data error. Since we're after the full picture I thought it was worth throwing this into the mix.
120602. Jeff Freymueller at 16:54 PM on 25 April 2010
        Has Arctic sea ice returned to normal?
        #20 chriscanaris, warmer than average weather in the Arctic is still plenty cold enough to result in the formation of more sea ice, because the surface air temp is well below 0C. In any case, during the cold spell in North America, the area that was much warmer than average was more like the Hudson's Bay area -- well south of the Arctic Ocean and not really "Arctic". So I'm not sure why it seems "perhaps counterintuitive" that when a cold air mass moves south, it is replaced by other air that in this case was warmer (as opposed to leaving a vacuum in the north?), and in any case the "warm" temperatures in that area were still below freezing, and not in the Arctic Ocean. I don't remember the situation north of Europe -- that may have been more relevant for Arctic sea ice formation, but I just don't recall.
120603. hu? at 16:49 PM on 25 April 2010
        Trenberth can't account for the lack of warming
        Where in Ternberth 09 does it state that satellites indicate an energy gap?
120604. Jeff Freymueller at 16:45 PM on 25 April 2010
        Has Arctic sea ice returned to normal?
        #18 HumanityRules: "In fact you could actually accuse SkepticalScience of cherry picking by changing from ice extent, which no longer shows what it would like to report, to ice volume which is more convinient." I'm sorry, HR, but this is a really silly statement. If you want to talk about the AMOUNT of sea ice, you really should be talking about the VOLUME of sea ice (or the MASS, if you like). Extent is useful, but it is not volume. The point is that volume has always been more important than extent, but the continuous time series of extent estimates goes back a lot longer. So there is value in measurements of both extent and volume, but they need to be interpreted based on what they are.
120605. RSVP at 16:24 PM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Sorry about my post 21. Very ambiguously written sentence. I meant that ice in general keeps things cooler, so thin ice is not going to help. The thicker the better, obviously.
120606. RSVP at 16:17 PM on 25 April 2010
        Has Arctic sea ice returned to normal?
        The increase albedo that Steve L refers to should actually help cooling (looking forward in time). On the other hand, thinner ice is more than a proxy (referring to Gestur's use of the word), as it actually influences climate acting as buffer (energy storage sink) to maintain a cooler planet.
120607. chris1204 at 12:27 PM on 25 April 2010
        Has Arctic sea ice returned to normal?
        I would hardly expect sea ice to 'normalise' so rapidly as to be back to normal within a year. The problem here is that both sides of the debate love cherries :-). I do recall recent arguments on this site suggesting that the recent extreme cold weather in Europe and Northern hemisphere generally was effectively a result of warmer weather in the Arctic - perhaps counterintuitive if we have evidence of new ice formation. Moreover, any recovery in ice cover can only begin with newer ice - you can't expect old ice to appear save with the passage of time. Marcus @ 1 points out that new ice is more vulnerable to melting - well, of course. But we don't know how much will melt and how much will eventually form part of old ice until we see the impact of the coming summers and the following winters. Steve L @ 6 notes the possible relevance of albedo with increased ice extent. Steve seems to believe this will ultimately be cold comfort (dreadful pun, I know) to the sceptical camp. John D @ 15 speaks of the contribution of wind forcings. The reality is that we're dealing with highly complex systems. Marcel Bökstedt @ 5 highlights this well. Extrapolations from one winter's data mean little irrespective of where you stand in the warmist - sceptical spectrum.
120608. Alexandre at 12:12 PM on 25 April 2010
        Has Arctic sea ice returned to normal?
        HumanityRules #18 I'm not sure that you understand what cherry picking is. It's to select carefully just the fraction of data that supports what you want to be true. Like picking Germany and Austria in Europe and say "my sampling shows that virtually all Europe speaks German". Watts does not "cherry picks sea ice extent" (as a parameter). He just picks a moment of near-average sea ice extent and shouts "it's back to normal!", as if the problem, if once existed, would be gone now. He does not analyse the whole dataset - he cherry-picks the convenient moments. If he did analyse the whole thing, he would find this near-average blip is as insignificant as the Jan 2008 cool spell as far as the trend is concerned.
120609. HumanityRules at 10:02 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        11.Jeff Freymueller and others Honestly the way you talk you would think Watts invented sea ice extent. All the international and national bodies that concern themselves with Arctic sea ice generally use ice extent as their primary measure. For example NSIDCto make their monthly assessement and daily measurements in terms of ice extent, and I'm not cherry picking NSIDC to make a point either. It's just a ridiculous claim to say Watts cherry picks ice extent. I checked his blog he's been reporting this metric back to 2007 when it was showing the all time low. In fact you could actually accuse SkepticalScience of cherry picking by changing from ice extent, which no longer shows what it would like to report, to ice volume which is more convinient. I actually don't believe this I understand John's wish to show the full story but I equally think you can't really blame Watts for using the 'standard' metric. I still wonder why all the international and national bodies don't use ice volume as their standard metric?
        Response: NSIDC and other organisations use sea ice extent but none of them use sea ice extent to say "Arctic sea ice has returned to normal". It's entirely appropriate to refer to sea ice extent and citing sea ice extent is not the issue here.
        
        The issue is the conclusions you draw from the sea ice extent data. It's inappropriate and misleading to say sea ice has returned to normal based on extent data because this is decidedly not the case - the total amount of sea ice is at record low levels.
        
        So the major point here is that citing sea ice extent data needs to be interpreted in proper context, being aware that the thicker ice below the surface is thinning and that total sea ice is at record low levels at the moment.
        
120610. mdenison at 09:46 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        It appears to me that the skeptics confuse average with normality. They suggest that an average extent recorded for March from 30 years of data represents normality. It does not. Normal sea ice extent is probably better taken as the extent in 1970 or earlier where the records show a long period of steady not declining cover. After that the extent declines so any average of recent data is below the starting point and not useful as a definition of normality. Sometimes average can be used to mean normality and arguments are made where the two terms are interchangeable. This is not the case here. The skeptics deliberately make a false argument by exploiting the fact that these different concepts may be treated as equivalent by the unwary reader.
120611. kdkd at 09:37 AM on 25 April 2010
        Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
        Would it be possible to do an RSS feed of comments for the site?
        Response: It's already available - look for the RSS icon in the left margin with 'Comments' below:
        
        http://www.skepticalscience.com/comments.xml
120612. Gestur at 08:48 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Another issue with sea ice extent that seems to me to be of importance for its use as a proxy for more relevant metrics like volume as well as for its policy uses derives directly from its low cut-point definition (at least 15% ice covered). Just in terms of coverage itself, two years with equal over-all total sea ice extent, say X million square km, could represent very different amounts of equivalent amount of surface area covered 100% with ice (i.e. what might be called ‘full-ice equivalent’ sea ice extent): say, 0.80 × X million square km in one case and in another, say, 0.40 × X million square km. This would obviously have very different implications for the albedo effect, among other policy-relevant considerations. Indeed, this ‘full-ice equivalent’ sea ice extent metric may well be declining even as the over-all total sea ice extent is gaining, depending on conditions, etc.
120613. johnd at 08:46 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        This report may be of some relevance. Apologies if it has been posted before. http://www.jamstec.go.jp/frsgc/research/d2/masayo.ogi/2009GL042356-pip.pdf Abstract Based on a statistical analysis incorporating 925-hPa wind fields from the NCEP/NCAR Reanalyses, it is shown that the combined effect of winter and summer wind forcing accounts for 50% of the variance of the change in September Arctic sea ice extent from one year to the next ( Δ SIE) and it also explains roughly 1/3 of the downward linear trend of SIE over the past 31 years. In both seasons meridional wind anomalies to the north and east of Greenland are correlated with September SIE, presumably because they modulate the export of ice through Fram Strait. Anticyclonic wind anomalies over the Beaufort Sea during summer favor low September SIE and have contributed to the record-low values in recent summers, perhaps by enhancing the flux of ice toward Fram Strait in the trans-polar drift.
120614. michael sweet at 06:54 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        One reason the NSIDC uses the extent is because it is easy to defend. It is a simple measurement and they have 30 years of data. To obtain the ice area you need to massage the data. Cryosphere Today displays the ice area because they think it is a better measure. Good scientists can disagree on small points. WUWT criticizes the NSIDC for using the SSM/I sensor instead of using the similar AMSR-E sensor. The NSIDC website states that the SSM/I sensor is more precise (the year to year variation is less) but the AMSR-E sensor is more accurate (the measured value is closer to the true value). The difference between the two sensors is small, but WUWT still complains about not using the more accurate value (WUWT does not seem to understand precision versus accuracy). NSIDC values the long term precision for their records. The volume data require even more processing (including a model!) so WUWT would have a fit if a change to that measure was made. In the end the long term trend will win out. If the ice volume is really that much lower the next summer that has conditions favoring melt will really melt. If the volcano in Iceland goes on for a long time it might affect sea ice this summer. We will have to wait until September to see what happens this summer. WUWT will always spout off when there is a small shift toward recovery, even if it is just noise in the data. They will quiet down when the cycle goes back to the long term trend.
120615. actually thoughtful at 05:34 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Every year in March the skeptics claim everything is fine. Every year, in September the pro-AGW sides claims things are not going well. I think it argues against looking at any year or short span of years. While volume does seem the superior measure, the 5 years of consistent data available are insufficient to make a solid claim (although even at 5 years the data is a notable counter to "ice extent is recovering").
120616. Marcel Bökstedt at 04:54 AM on 25 April 2010
        Tracking the energy from global warming
        Berenyi Peter> Interesting post! (1) How can we be sure that there is no CO2 deep mixing? I agree, if we do know that, it makes it harder to invent a mechanism for sending the energy down to Davy Jones. (2) I believe that the measured OHC has been increasing lately. The rate of increase has fallen though. If I understand your realignment of the OHC and the TOA measurements correctly, the model accepts the recent value of OHC. So why do you say that we have been loosing energy lately? But maybe this is not so important, it seems to me that the main point you are making is that - as you stated earlier - this is not a disagreement between two datasets, its a disagreement between data and theory. I agree, something has to give, either the data or the theory. It will be interesting to see who will win. We should remember that all of this is a higher order question. The first theoretical question to ask about AGW is "how would a given amount of CO2 affect climate". This is essentially a question of finding an equilibrium (yeah, I know I'm simplifying here). The second, more difficult one, is "how will we pass from the present climate to the one forced by the CO2". This is to ask for the path through which a system reaches the equilibrium. That was all theory, but if we can answer those questions, we can compare the result with observations. Well, we can't compare the answer to the first question with observations, but if we can figure out the more difficult second part of the theory, we can compare that. And at present this comparison with observations has difficulties.
120617. Riccardo at 03:48 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        During winter sea ice extent (or area) is largely determined by the weather at the margin of the ice sheet, i.e. at relatively "low" latitudes. Last winter has been cold at these low latitudes but the arctic at higher latitudes was warmer. This is an example of the interannual varibility that says nothing about the trend. And this is why it makes no sense to say that from 2007 arctic sea ice has recovered. Unless one means that the this year number is higher, which no one doubts, a recovery or reversal of the trend cannot be assessed nor we have (at the moment, at the very least) reasons to believe it's going to happen.
120618. Jeff Freymueller at 02:18 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        #3 HumanityRules, measuring sea ice extent is a fairly simple mapping problem given satellite imagery. I would expect that the extent measurement is largely or totally an automatic process given the input images. Measuring volume requires you to measure the thickness of the ice as well, and until the last several years that required making thickness measurements by direct sampling, submarine, or some other method. Even now, I think it takes more work than measuring extent. In the past, it would have taken a lot of work to make that estimate. So there is nothing wrong with reporting extent or discussing it. You just have to keep in mind what extent is, and what it is not. It is sea ice cover, and not sea ice volume. If you have ever watched the ice break up on a frozen lake, you will know that cover and volume can have very little to do with each other. If Watts is trumpeting a claim that sea ice has returned to normal because extent has returned to normal, while at the same time volume data show the lowest volume yet recorded, then cherry-picking is about the kindest assessment you can make of that.
120619. Alexandre at 01:49 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Marcel #9 Understood. Answering this good question of yours would be the role of a cause attribution study. I think I already saw one about this issue somewhere.
120620. Marcel Bökstedt at 01:40 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Ian Forrester> Yes, the submarines give a point in favour of the model. It does not look like a strong confirmation; there seems to be deviations on the order of meters of thickness. Also, it's hard to evaluate the quality of the submarine measurements from the web page. Maybe someone knows more about this? Alexandre> My question was not about AGW or not, but about the connection between the warming of the Arctic and the loss of ice. I just wanted to make the point that this connection might be more complex than what one would immediately assume.
120621. suibhne at 01:15 AM on 25 April 2010
        Where is global warming going?
        chris The anticipated comment to which I refer; The reference is: Joshua Halpern, Christopher M. Colose, Chris Ho-Stuart, Joel D. Shore, Arthur P. Smith, Jörg Zimmermann (2010) Comment On “Falsification of the Atmospheric CO2 Greenhouse Effects within the Frame of Physics”, (to appear in) International Journal of Modern Physics (B), Vol 24, Iss 10, March 30 2010. The six authors put in some hard work to find any alleged "flaws" in the G&T paper. The previous "refutations" unfortunately did not cut the mustard. I for one was rather surprised by the approach of some of previous attempts. I think any reasonable person would agree that it is wrong to prejudge the as yet unpublished comment. If and when it is published however I would expect to have some observations which I will share with the Deltoids.
120622. Alexandre at 00:47 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Marcel #5 Scientific papers often use the expression "this is consistent with..." instead of categoric assertions like "this is proof that...". There are lots of evidence pointing to AGW. Arctic ice loss is just one of them. Is it possible that other factors concur (as you rightly pointed out)? Sure. Do we have any evidence of that? Hardly. I think of it like a crime investigation. The accused was seen entering the victim's house before the estimated time of the murder, and a car like his was seen leaving the neighborhood an hour later. The crime weapon was his property, and his hand had the chemical marks of firing the gun. He had the gun when the cops searched him afterwards. The victim had an affair with the accused's wife (there was a motive). Does it prove beyond refutation the accused is guilty? Not quite. We can imagine some unlikely story in which he practiced shooting in his backyard and went to a friendly visit to the victim, and a third party stole his gun for an hour just to make him look guilty. But there's no evidence of this made-up story. On the other hand, do we have enough information to take concrete measures about it (eg convict the accused)? Most likely. Your question is a good one, and maybe some other commenter here knows a cause attribution study about this ice loss. I just feel it's important to keep the issues in perspective.
120623. Ian Forrester at 00:45 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Marcel Bokstedt said:

        Zhang's thickness graph above goes back to 1980, but it seems to be based on models, so we only believe it if we believe in those models.

        However, if you read the linked information you will see that Zhang's model has been confirmed by recently released US Naval measurements from it's under polar ice submarine patrols.

        PIOMAS has been extensively validated through comparisons with observations from US-Navy submarines, moorings, and satellites.

120624. Steve L at 00:27 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        I agree that sea ice extent may not be the best metric of a warming Arctic, and I imagine the choice of the 15% cut-off adds to this, while sea ice volume should be better (given that it can be measured well). But sea ice area is quite important mechanistically in terms of albedo. Therefore I'm fine with skeptics focusing on extent. It will come back to bite them in the end, though, since you can only spread a given volume so thin.
120625. Sean A at 00:26 AM on 25 April 2010
        The significance of past climate change
        "Using ice cores, we can work out past temperature change, the level of solar activity plus the amount of greenhouse gases and volcanic dust in the atmosphere." A bit of explanation on how all that information can be gleaned from ice cores might be helpful. Isn't this an important feedback... in the past, during a warming trend, increasing temperatures caused the oceans to release dissolved CO2, which caused further warming.
120626. Marcel Bökstedt at 00:20 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        When you look at graphs of Arctic sea ice extent plotted against time, graphs like the one John posted above, two conclusions seem visually obvious. There are very large random fluctuations, and there is a very clear long term decreasing trend. Because of the large short time variations, I don't think that one shoud be too impressed by either the sea ice minimum of 2007 or by the alleged recovery. These could be random events, and do not touch the long term trend. The available data on ice thickness are strongly suggestive, but they only span about 5 years. Because we already know that we have to deal with strong short time variations, it is not clear to me that they do represent a long term trend. Zhang's thickness graph above goes back to 1980, but it seems to be based on models, so we only believe it if we believe in those models. Still, the data on ice extent very clearly points to a trend towards less ice. The most obvious explanation would be global warming. But is it certain that this decrease is linked to that - yes, it does sound like a very foolish thing to say, but after all, we know that the situation in the Antarctic sea is very complicated. The sea around Antarctica is warming, but the extent of ice in that warming water is increasing. There are several interesting attempts to explain this, including a subtle model by Jinlun Zhang et al., but I don't think that we really understand what is going on there. If we don't understand the dynamics of ice around Antarctica, how can we be sure that we understand the dynamics of ice around the North Pole?
120627. Alexandre at 00:16 AM on 25 April 2010
        Has Arctic sea ice returned to normal?
        Watts -as most deniers- is a cherry picker. I remember when he cheerfully tried to capitalize on the 2008 La Niña temperature drop, and now totally ignores the recent temperature rise. Many people believe him, but that's just the human problem of sticking to anyone that says what one wants to listen. It does not have anything to do with the quality of data, or accuracy of analysis.
120628. Ken Lambert at 00:03 AM on 25 April 2010
        Tracking the energy from global warming
        BP #72 Your post #67 explains that the last 6 years (2004-2010) of the TOA curve in your G62 graph is the same shape as the G60 graph (slightly negative trend slope) except that the G62 is sitting on a linerr positive trend slope which represents a systemic offset error in the CERESFlash TOA flux. Right? I subtract the two trend slopes and come up with a positive slope difference which equates to 1.11E22J/year which equates to a TOA flux error of +0.69W/sq.m Is not that an estimate of the 'large and unknown' CERES TOA flux error, derived from your G60 and G62 graphs? We all agree that CERES tolerances of 2 +/-5 W/sq.m is a useless number for evaluating radiative forcing imbalances. You have said that CERES TOA is high precision but low accuracy, meaning that it is good for relative measures wrt time, but no good for absolute numbers. You claim that the 2004-10 Argo OHC measurements are the opposite - presumably no good for relative time series comparisons but good for absolute numbers. So if your G60 graph is meaningful - it does provide a way of calibrating the CERESflash TOA flux with an absolute number derived from assuming that Argo measured OHC heat (top 700m) energy absorbed equals the integral of the CERESflash TOA flux. Right? If that is not right, please explain why. Your last papagraph in #72 is confusing - "Effective temperature of Earth as seen from space should have decreased by 0.15 °C if climate sensitivity is 3 °C for carbon dioxide doubling as claimed." Did you mean 'increased by 0.15 degC' for a 5% CO2 increase and that equates to 0.56 W/sq.m extra energy flux imbalance at TOA? Was this a sardonic remark doubting the existence of the 0.56 W/sq.m of extra radiative forcing from 5% increase in CO2? You also have a major problem with von Schukmann finding lots of heat down to 2000m from the Argo buoys. I noticed that Dr Trenberth has already used this VS paper as evidence for his 0.45W/sq.m (0.9 postulated and 0.55 found)of missing heat in his email exchange with Dr Pielke Snr. What about mechanisms like the thermohaline circulation to get heat down to 2000m in these short timeframes?? BP, I think you are on the right track with your posts, so please expand your ideas into language more accessible to the non-expert climateer (dumber engineers like me). You might yet be the man to crack the AGW case..
120629. HumanityRules at 23:56 PM on 24 April 2010
        Has Arctic sea ice returned to normal?
        A genuinely puzzling question. If ice volume is a better gauge of arctic sea ice and if the trend is more worrying why is this not regularly used as the standard for measuring arctic sea ice condition? The way you word things it sort of suggests that WUWT are cherry picking the ice extent to tell a certain story. But most of the serious science website that provide day-to-day arctic sea ice coverage focus on ice extent as well (NSIDC, arctic roos, DMI, cryospere today etc). Are there uncertainties with measuring ice volume?
120630. Marcus at 23:24 PM on 24 April 2010
        Has Arctic sea ice returned to normal?
        Also, I do find it amusing that the skeptics leap on a single years worth of "good" news to prove their point, yet they're the quickest to dismiss even a few years of *bad* news, claiming its insufficient to prove a trend. They certainly score zero points for consistency ;)!
120631. Marcus at 23:22 PM on 24 April 2010
        Has Arctic sea ice returned to normal?
        As I understand it, one of the key problems with a reliance on sea-ice extent is-whilst you may have one good year of ice recovery-that this ice will be relatively new & thus more prone to melting come the next Summer. As I also understand it, what concerns scientists is the lack of multi-year ice. For my part, when non-specialized trade vessels can sail the extent of the North-West Passage-in late Autumn-then there is something to be concerned about!
120632. chris at 19:08 PM on 24 April 2010
        Where is global warming going?
        re: suibhne at 18:03 PM on 24 April, 2010 Not really suibhne. Arctic sea ice is on a downward trend. Sea ice area coverage will obviously show considerable interannual variation; however as the downward trend progresses strongly warming years will eat into old ice which requires several sufficiently cool years to recover, and so sea ice volume is likely to be diminishing without the amount of interannual variability of sea ice area. Thus, as pointed out by Peter Hogarth evidence indicates that total sea ice (i.e. sea ice volume) in March was the lowest March sea ice volume on record: Polar Science Center, Univ. Washington re: suibhne at 18:12 PM on 24 April, 2010 suibhne, jibal was referring to your curious reluctance to address straightforward questions on the Deltoid thread. He wasn't referring to the in press comment on the dodgy IJMBP paper.
120633. suibhne at 18:12 PM on 24 April 2010
        Where is global warming going?
        jibal at 16:48 PM on 22 April, 2010 Jabal refers to another site where the imminent release of a comment by Halpern, Smith, Colose and three others was promised (March 20). As this has not happened as yet it might out of courtesy to them be better to wait for its release. http://scienceblogs.com/deltoid/2009/03/gerlich_and_tscheuschner_oh_my.php
120634. suibhne at 18:03 PM on 24 April 2010
        Where is global warming going?
        James Wight 37 Your figures for Arctic Sea Ice may need an update. Now highest for last 8 years. http://wattsupwiththat.com/
120635. damien at 14:16 PM on 24 April 2010
        Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
        This repository is awesome. Can you publish statistics on the number of articles published in each "camp" for comparative purposes? For example a plot of number of articles in a category for each month, with the option of comparing graphs side by side. Also, it would be helpful for the Peer Reviewed articles if it listed the actual journal/conference it was published, not just springerlink.com, which could be any number of journals.
120636. kdkd at 13:42 PM on 24 April 2010
        Tracking the energy from global warming
        I'm really not convinced of the validity of treating a stochastic system as if it deterministic. Seeing as the OHC/TOA system is certainly part of a stochastic system, we'd need a good bit more data than 9 annual cycles (the annual cycle should be the basic unit of analysis here) in order to understand properly the contribution to the climate system. Given the similarities with the global temperature record (another part of the system), around 30 years of data would be a bare minimum with which to reach robust conclusions.
120637. Berényi Péter at 13:01 PM on 24 April 2010
        Tracking the energy from global warming
        #70 Ken Lambert at 23:45 PM on 23 April, 2010 This converts to a systemic error of +0.69W/sq.m in the CERESflash flux. I don't think so. The systematic error is large and unknown. Net flux at TOA is estimated to be 2 ± 5 W m^-2, i.e. even the sign is doubtful. In this sense TOA flux is not measured at all by CERES. However, interannual variation is much better constrained. The large difference between figures in #60 & #62 comes from OHC. The transition around 2003 from MBT/XBT stuff to ARGO has a huge intercalibration problem. That is how the "missing heat" was produced. If the unknown offset of CERES FLASHFlux is aligned to the early 21th century OHC data, one gets a positive slope but poor fit with much missing thermal energy by the end of this decade. On the other hand, if it is done the other way around and FLASHFlux is aligned to the late part of OHC, the fit is excellent except before mid 2003. In this case we do not have any recent "missing heat", but excess heat before 2003. My guess is the thermal energy was there, in the upper 700 m of oceans, just was not measured properly (e.g. in southern Pacific). In this case one does not have to invent mysterious processes transferring heat into the abyss directly through a 700 m deep cooling layer. What is more, this process would only carry heat, but not dissolved carbon dioxide. After all CO₂ deep mixing is supposed to be extremely slow. So far so good. However, we still have a problem. Not with measurement, but with theory. OHC and net TOA flux measurements can be made consistent, but at a price. We have a negative energy balance for the last six years. The climate system is not gaining energy, but losing it. A -118 mW m^-2 rate may not sound much, but is enough to bring havoc to standard greenhouse theory. It is about the decrease in TSI (Total Solar Irradiance) due to weak and late cycle 24. But wait, CO₂ has increased from 375 ppmv to 389 ppmv between 2003 & 2010. The change in radiative forcing during this period is about 5% of a CO₂ doubling. Effective temperature of Earth as seen from space should have decreased by 0.15 °C if climate sensitivity is 3 °C for carbon dioxide doubling as claimed. It is equivalent to a positive energy imbalance of 560 mW m^-2 at TOA, which is not seen.
120638. Alexandre at 07:55 AM on 24 April 2010
        Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
        Now that we don't have that "skeptical article of the week" anymore, how's the argument ranking position defined?
        Response: On the latest articles page, they're ranked by date from latest to earliest.
        
        If anyone misses the Skeptic of the Week feature, I can easily add that back in - I just commented out the code.
        
120639. chris at 07:11 AM on 24 April 2010
        Earth's five mass extinction events
        batsvensson at 05:15 AM on 19 April, 2010 batsvensson, I told you in detail why I reject your idea. If you don't agree, you really need to say why! If you can "imagine" "scenarios" "which (my) list seams not to contradict", you really need to tell us what these scenarios are. We can hardly be expected to address ideas that are in your "imagination", that you don't tell us about. We aren't mind-readers!
120640. chris at 06:27 AM on 24 April 2010
        The significance of past climate change
        Steve Berry at 04:57 AM on 24 April, 2010 Steve, the Earth's thermal energy comes almost exclusively from the sun (a tiny amount from radioactive decay within the Earth). Since greenhouse gases are largely transparent to solar radiation of the energies that directly impact the atmosphere and the Earth, enhanced greenhouse gases don't have much of an effect on incoming solar radiation, which impacts those regions of the Earth's atmosphere and surface that are facing the sun (i.e. during daylight hours). On the other hand radiative equilibrium (largely constant Earth surface temperature) is achieved by the incoming solar radiation being balanced by radiation returning to space. Some of this occurs by reflection [from the atmosphere, or clouds or highly reflective (high albedo) Earth surface, especially surface ice]. A large part of the radiation returning to space is that which is emitted from the Earth's surface. This is long wave infra red (LWIR), that is emitted by all bodies that have temperatures above zero Kelvins. It is this thermal radiation that is "trapped" by greenhouse gases and which warms the atmosphere. LWIR is an inherent property of all warm bodies, and occurs continuously, including during the night. So whereas daytime temperatures are dominated by the incoming solar radiation (depends on incident angle; i.e. seasonality) and reflective cloud cover, night time temperature variability is dominated by warmth trapping cloud cover and the efficiency of emission of LWIR back to space. All else being equal (i.e. solar irradiation, albedo and cloud cover), in a world with continuously rising greenhouse gas concentrations, we expect the night time temperatures to increase faster than day time temperatures, since LWIR is only one of several contributions to loss of thermal energy to space during the day, whereas it is a dominant factor in night time heat loss. This isn't the whole story. In a warming world we might expect to observe somewhat higher cloud cover at night, since enhanced atmospheric temperatures means more atmospheric water vapour with possible enhanced cloud formation as the atmosphere cools at night. On the other hand, man made increases in atmospheric greenhouse gases is accompanied by enhanced atmospheric aerosols, and this tends to decrease solar radiation at the Earth's surface, reducing the night/day warming difference...
120641. Tom Dayton at 06:22 AM on 24 April 2010
        The significance of past climate change
        RSVP, greenhouse gas radiation does not cancel out, because the gas acts as layers instead of a single slab. Each layer radiates in all directions. When a layer has another layer above it, that upper layer in turn intercepts the radiation that is headed toward space, then radiates it in all directions, including down. I'll not finish the explanation here, because you can read it on Spencer Weart's Simple Models of Climate page. Use your browser's Find function on that page to find the text "shorthand way," and read down from there.
120642. physicalscientist at 06:22 AM on 24 April 2010
        Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
        John - Thank you very much for the collated links to peer-reviewed papers. This is a valuable service and it will be very helpful for students and others less familiar with the list of reputable journals to find appropriate material. Don't worry too much about the skeptic, neutral, pro-AGW classifications, we can figure it out. Although I would probably fall in the 'pro-AGW' camp, I definitely am not really pro-AGW. It actually would be much better if the deniers were right and we had nothing to worry about. Unfortunately, we definitely do.
120643. KR at 05:05 AM on 24 April 2010
        The significance of past climate change
        Unrecovered, here where you talk about understanding positive feedback, you have a good point. Many people seem to assume that positive feedback is unstable. One way to explain this is to note that positive feedback results in the system moving further from the starting point than the unmodified forcing would take it. That extra change causes more feedback, and so on, and so on. If the feedback is <1x the change, each successive feedback amount is smaller, and the sum of all the changes damps out. If the feedback is >1x the change, however, each iteration of feedback will be larger, and the system will run away (until some other form of feedback limits matters). Fortunately the vast majority of systems are stable - I suspect unstable ones just blow up when they arise.
120644. Steve Berry at 04:57 AM on 24 April 2010
        The significance of past climate change
        Can someone explain to me why most of the observed global surface warming of recent decades is occurring mostly at night? Why, if CO2 is a warmer, is it that daytime temps have remained pretty much stable, but nighttime temps have risen? Wouldn't this indicate that increased cloudiness is a major factor? Thanks.
120645. RSVP at 04:45 AM on 24 April 2010
        The significance of past climate change
        Incremental CO2 in the atmosphere could just as easily act as a staging for additional IR radiation. Why not then consider this as providing as much negative feedback as positive feedback (basically resulting in a net canceling towards warming)?
120646. garythompson at 03:47 AM on 24 April 2010
        The significance of past climate change
        #73 chemware - if you were to plot the average global monthly surface temperatures anomolies from HADCRUT3 vs. Mauna Loa average monthly CO2 concentrations you would not get a very nice correlation. from 1958 to 1974 there was a flat response, followed by a linear reponse (and what appears to be good correlation) then back to a flat response in 1999 which continues today. it just shows there are other variables at play here.
120647. Chris G at 03:16 AM on 24 April 2010
        The significance of past climate change
        Mikko, good point, I try to make point this out whenever I hear complaints about cows or local grassland burning. Chemware and Barry, Interesting graphs, but I think there are a couple of major flaws, one each per graph. On the temp graph, it's pretty well established that temperature response is logarithmic, and you have applied a linear best-fit. Hansen tends to be on the upper end of estimates for long-term equilibrium response, and I think he's estimating about 6 K for a doubling of CO2, under current planetary conditions. Aside from thermal expansion, there is a hard limit of how much sea levels can rise that is determined by how much ice there is to melt. Even if you accept that the earth will eventually be ice-free if a 450 or greater ppm level is maintained, there's only about 80 m of ice available. In contrast, you graph is off the chart at 450 ppm. http://pubs.usgs.gov/fs/fs2-00/
120648. bookworm at 02:48 AM on 24 April 2010
        The significance of past climate change
        might be useful to look at the reverse situation. If climate had NOT changed significantly in the past, change skeptics would then be arguing that man could not possibly have any effect on world climate - that climate is self correcting in response to various challenges. The only overall conclusion from the fact of past change is that future change is possible. As other posts have pointed out the skeptic argument above is really a non-sequitur. reversing the situation helps people understand that. Only then get into the details - discussions of time scales and the like.
120649. kdkd at 23:54 PM on 23 April 2010
        Tracking the energy from global warming
        Just to confirm, if I annualise the TOA/OHC data rather than have it in quarters like at the moment (actually over 9 years), neither the regression nor the correlation give statistically significant parameter estimates due to the loss of statisical power.
120650. Ken Lambert at 23:45 PM on 23 April 2010
        Tracking the energy from global warming
        BP #67 Think I have got it. Excuse my slower engineer's brain. If we can name your charts Graph #60 and Graph #62, then am I right in assuming that your G#60 is the 'right' measure of OHC because the integral of the TOA flux fits the Argo 700m OHC? If so, then the diffence in slopes of the TOA integral between G#60 and G#62 represents the systemic error in the CERESflash flux. Taken over the last 6 years, your G#60 slope is -0.19E22J/yr and the G#62 slope is about +0.92E22J/yr with the difference being about 1.11E22J/yr. This converts to a systemic error of +0.69W/sq.m in the CERESflash flux. Could you then suggest why the 2000 - 2004 part of your G#62 TOA curve has a pretty flat slope of about 0.25E22J/yr, implying a much lower systemic error or if the error is constant at +1.11E22J/yr; a large decline in OHC for 2000-2004?

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